Play With Intensities.

saturate.cpp

// Scan Images and Modify.
#include<iostream>
#include "cv.h"
#include "highgui.h"
#include <cstring>
using namespace cv;
using namespace std;


void saturate(Mat image, int c, int increase)
{
	// No of channels in the current input image.
	int channels = image.channels();

	// if image is gray scale then number of channels is 1.
	if(channels == 1)
	{
		// create iterator for image and initialize it with the first element.
		// First element is returned by begin<uchar>() function.
		// Since we know that image is gray scale and we have assumed that the input
		// image is of 8 bit representation format we pass uchar or unsigned char as a
		// return data type to begin() function.
		// Similarly end() returns location of the last element of the container.
		for(typeof(image.begin<uchar>()) it = image.begin<uchar>(); it!= image.end<uchar>() ; it++)
		{
			// *it is the value pointed by iterator it.
			*it += increase;
		}
	}
	// if we have color input
	else if(channels == 3)
	{
		// Since input is a color image, every pixel represents a vector of size 3.
		// Vec3b is data type which represents Vector of length 3 where each element is uchar
		for(typeof(image.begin<Vec3b>())it = image.begin<Vec3b>(); it!= image.end<Vec3b>(); it++ )
		{
			// c represents channel number.
			(*it)[c]+= increase;
		}
	}
}

int main()
{
	// path of image.
	string path = "res/download.jpg";

	// read color image
	Mat image = imread(path,CV_LOAD_IMAGE_GRAYSCALE);

	if(!image.data)
	{
		cout<<"fail\n";
		return -1;
	}

	// create clone of the image.

	Mat In = image.clone();

	// Function which adds increases intensity of every pixel in image by given value.
	saturate(image,1,40);

	namedWindow("original",CV_WINDOW_AUTOSIZE);
	namedWindow("out",CV_WINDOW_AUTOSIZE);
	imshow("out",image);
	imshow("original",In);
	waitKey(0);
	imwrite("res/original.png",image);
	imwrite("res/out.png",In);
	return 0;
}